ABSTRACT: The discovery of cytosine hydroxymethylation (5-hmC) as a mechanism that potentially controls DNA methylation changes typical of neoplasia prompted us to investigate its behavior in colon cancer. 5-hmC is globally reduced in proliferating cells such as colon tumors and the gut crypt progenitors, from which tumors can arise. Here, we show that colorectal tumors and cancer cells express Ten-Eleven Translocation (TET) transcripts at levels similar to normal tissues. Genome-wide analyses show that promoters marked by 5-hmC in normal tissue, and those identified as TET2 targets in colorectal cancer cells, are resistant to methylation gain in cancer. In vitro studies of TET2 in cancer cells confirm that these promoters are resistant to methylation gain independently of sustained TET2 expression. We also find that a considerable number of the methylation gain-resistant promoters marked by 5-hmC in normal colon overlap with those that are marked with poised bivalent histone modifications in embryonic stem cells. Together our results indicate that promoters that acquire 5-hmC upon normal colon differentiation are innately resistant to neoplastic hypermethylation by mechanisms that do not require high levels of 5-hmC in tumors. Our study highlights the potential of cytosine modifications as biomarkers of cancerous cell proliferation. DNA methylation levels were measured in genomic DNA extracted from primary colon tissues.

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Project description:The discovery of cytosine hydroxymethylation (5-hmC) as a mechanism that potentially controls DNA methylation changes typical of neoplasia prompted us to investigate its behavior in colon cancer. 5-hmC is globally reduced in proliferating cells such as colon tumors and the gut crypt progenitors, from which tumors can arise. Here, we show that colorectal tumors and cancer cells express Ten-Eleven Translocation (TET) transcripts at levels similar to normal tissues. Genome-wide analyses show that promoters marked by 5-hmC in normal tissue, and those identified as TET2 targets in colorectal cancer cells, are resistant to methylation gain in cancer. In vitro studies of TET2 in cancer cells confirm that these promoters are resistant to methylation gain independently of sustained TET2 expression. We also find that a considerable number of the methylation gain-resistant promoters marked by 5-hmC in normal colon overlap with those that are marked with poised bivalent histone modifications in embryonic stem cells. Together our results indicate that promoters that acquire 5-hmC upon normal colon differentiation are innately resistant to neoplastic hypermethylation by mechanisms that do not require high levels of 5-hmC in tumors. Our study highlights the potential of cytosine modifications as biomarkers of cancerous cell proliferation. messenger RNA levels were measured in total RNA extracted from primary colon tissues. Normal away are at least 20cm from tumors.

Project description:The discovery of cytosine hydroxymethylation (5-hmC) as a mechanism that potentially controls DNA methylation changes typical of neoplasia prompted us to investigate its behavior in colon cancer. 5-hmC is globally reduced in proliferating cells such as colon tumors and the gut crypt progenitors, from which tumors can arise. Here, we show that colorectal tumors and cancer cells express Ten-Eleven Translocation (TET) transcripts at levels similar to normal tissues. Genome-wide analyses show that promoters marked by 5-hmC in normal tissue, and those identified as TET2 targets in colorectal cancer cells, are resistant to methylation gain in cancer. In vitro studies of TET2 in cancer cells confirm that these promoters are resistant to methylation gain independently of sustained TET2 expression. We also find that a considerable number of the methylation gain-resistant promoters marked by 5-hmC in normal colon overlap with those that are marked with poised bivalent histone modifications in embryonic stem cells. Together our results indicate that promoters that acquire 5-hmC upon normal colon differentiation are innately resistant to neoplastic hypermethylation by mechanisms that do not require high levels of 5-hmC in tumors. Our study highlights the potential of cytosine modifications as biomarkers of cancerous cell proliferation. Six samples were analyzed. 2 biological replicates each of HCT116 cells stably transfected with an empty vector control (TET_KD_Plk), with shRNA to TET2 (TET_KD_2C) and with shRNA to TET2 and TET3 (TET_KD_2.3)

Project description:The discovery of cytosine hydroxymethylation (5-hmC) as a mechanism that potentially controls DNA methylation changes typical of neoplasia prompted us to investigate its behavior in colon cancer. 5-hmC is globally reduced in proliferating cells such as colon tumors and the gut crypt progenitors, from which tumors can arise. Here, we show that colorectal tumors and cancer cells express Ten-Eleven Translocation (TET) transcripts at levels similar to normal tissues. Genome-wide analyses show that promoters marked by 5-hmC in normal tissue, and those identified as TET2 targets in colorectal cancer cells, are resistant to methylation gain in cancer. In vitro studies of TET2 in cancer cells confirm that these promoters are resistant to methylation gain independently of sustained TET2 expression. We also find that a considerable number of the methylation gain-resistant promoters marked by 5-hmC in normal colon overlap with those that are marked with poised bivalent histone modifications in embryonic stem cells. Together our results indicate that promoters that acquire 5-hmC upon normal colon differentiation are innately resistant to neoplastic hypermethylation by mechanisms that do not require high levels of 5-hmC in tumors. Our study highlights the potential of cytosine modifications as biomarkers of cancerous cell proliferation. 5 normal colon samples and 4 matching tumor samples were profiled for 5-hydroxymethylcytosine content genomewide using hmeDIP-seq. The colorectal cancer cell line HCT116 was profiled for binding of TET2 genomewide by chromatin immunoprecipitation sequencing (ChIP-seq).

Project description:The discovery of cytosine hydroxymethylation (5-hmC) as a mechanism that potentially controls DNA methylation changes typical of neoplasia prompted us to investigate its behavior in colon cancer. 5-hmC is globally reduced in proliferating cells such as colon tumors and the gut crypt progenitors, from which tumors can arise. Here, we show that colorectal tumors and cancer cells express Ten-Eleven Translocation (TET) transcripts at levels similar to normal tissues. Genome-wide analyses show that promoters marked by 5-hmC in normal tissue, and those identified as TET2 targets in colorectal cancer cells, are resistant to methylation gain in cancer. In vitro studies of TET2 in cancer cells confirm that these promoters are resistant to methylation gain independently of sustained TET2 expression. We also find that a considerable number of the methylation gain-resistant promoters marked by 5-hmC in normal colon overlap with those that are marked with poised bivalent histone modifications in embryonic stem cells. Together our results indicate that promoters that acquire 5-hmC upon normal colon differentiation are innately resistant to neoplastic hypermethylation by mechanisms that do not require high levels of 5-hmC in tumors. Our study highlights the potential of cytosine modifications as biomarkers of cancerous cell proliferation. Overall design: Four biological replicates were analysed per cell type purified by flow cytometry using the CD24 marker and depletion of CD45 and Ulex lectin positive cells. See Wong et al. NatCellBiol 2012 Mar 4;14(4):401-8 or Buczacki et al. Nature 2013 Mar 7;495(7439):65-9. CD24Mid are also referred to as CD24low in the manuscript.

Project description:DNA methylation at the 5-position of cytosine (5-mC) is a key epigenetic mark critical for varius biological and pathological processes. 5-mC can be converted to 5-hydroxymethylcytosine (5-hmC) by the Ten-Eleven Translocation (TET) family of DNA hydroxylases. Here we report that &quot;loss of 5-hmC&quot; is an epigenetic hallmark of melanoma with diagonostic and prognostic implications. Genome-wide mapping of 5-hmC in nevi and melanomas for the first time revealed loss of 5-hmC landscape in the melanoma epigenome. Downregulation of Isocitrate Dehydrogenase 2 (IDH2) and TET family enzymes proved to be one of the mechanisms underlying the loss of 5-hmC during melanoma development, and rebuilding the 5-hmC landscape in the melanoma epigenome by reintroducing active TET2 or IDH2 suppressed melanoma growth and increased tumor-free survival. Thus, our study establishes that &quot;loss of 5-hmC&quot; is a new epigenetic hallmark of melanoma and links IDH and TET family enzymes-mediated 5-hmC putative tumor suppressor pathway to the suppression of melanoma progression. Determine the genome-wide distribution of 5mC and 5hmC in benign nevus tissue, melanoma tissue, A2058 MOCK cells (overexpressing empty vector), A2058 TET2 cells (overexpressing wild type human TET), and A2058 TET2M cells (overexpressing mutant human TET).

Project description:DNA methylation is tightly regulated throughout mammalian development and altered methylation patterns are a hallmark of cancer. The methylcytosine dioxygenase TET2 is frequently mutated in acute myeloid leukemia (AML) and has been suggested to protect CpG islands and promoters from aberrant methylation. By generating a novel mouse model of Tet2-deficient AML we show that loss of Tet2 in hematopoietic cells leads to progressive hypermethylation of active enhancer elements and altered expression of genes implicated in tumorigenesis. In contrast, CpG island and promoter methylation does not change in a Tet2-dependent manner. Furthermore, we confirm this specific enhancer hypermethylation phenotype in human AML patients. Thus, we propose that TET2 prevents leukemic transformation of hematopoietic cells by protecting enhancers from aberrant DNA methylation. Gene expression profiles from Tet2-/-;AML1-ETO and Tet2fl/fl;AML1-ETO in vitro-grown hematopoietic cells were compared using GeneChip Mouse Gene ST 2.0 Arrays (Affymetrix). Expression changes were investigated at early (passage 2) and late (passage 10) timepoints after Tet2 disruption.

Project description:DNA methylation is tightly regulated throughout mammalian development and altered methylation patterns are a hallmark of cancer. The methylcytosine dioxygenase TET2 is frequently mutated in acute myeloid leukemia (AML) and has been suggested to protect CpG islands and promoters from aberrant methylation. By generating a novel mouse model of Tet2-deficient AML we show that loss of Tet2 in hematopoietic cells leads to progressive hypermethylation of active enhancer elements and altered expression of genes implicated in tumorigenesis. In contrast, CpG island and promoter methylation does not change in a Tet2-dependent manner. Furthermore, we confirm this specific enhancer hypermethylation phenotype in human AML patients. Thus, we propose that TET2 prevents leukemic transformation of hematopoietic cells by protecting enhancers from aberrant DNA methylation. Enhanced Reduced Representation Bisulfite Sequencing (eRRBS) analysis of in vitro-grown hematopoietic cells transduced with AML1-ETO or MLL-AF9

Project description:DNA methylation is tightly regulated throughout mammalian development and altered methylation patterns are a hallmark of cancer. The methylcytosine dioxygenase TET2 is frequently mutated in acute myeloid leukemia (AML) and has been suggested to protect CpG islands and promoters from aberrant methylation. By generating a novel mouse model of Tet2-deficient AML we show that loss of Tet2 in hematopoietic cells leads to progressive hypermethylation of active enhancer elements and altered expression of genes implicated in tumorigenesis. In contrast, CpG island and promoter methylation does not change in a Tet2-dependent manner. Furthermore, we confirm this specific enhancer hypermethylation phenotype in human AML patients. Thus, we propose that TET2 prevents leukemic transformation of hematopoietic cells by protecting enhancers from aberrant DNA methylation. 5hmC-DIP-seq analysis for distribution of 5hmC in in vitro-grown hematopoietic cells transduced with AML1-ETO

Project description:Methylation at 5-cytosine (5-mC) is a fundamental epigenetic DNA modification associated recently with cardiac disease. In contrast, the role of 5-hydroxymethylcytosine (5-hmC) – 5-mC’s oxidation product – is unknown in the context of the heart. Here, we assess the hydroxymethylome in embryonic, neonatal, adult and hypertrophic mouse cardiomyocytes, showing that dynamic modulation of hydroxymethylated DNA is associated with specific transcriptional networks during heart development and failure. DNA hydroxymethylation marks gene bodies of highly expressed genes and distal regulatory regions with enhanced activity. Pathological hypertrophy is characterized by a partial shift towards a fetal-like distribution pattern. We further demonstrate a regulatory function of TET2 and provide evidence that the expression of key cardiac genes, such as Myh7 is modulated by TET2-mediated 5-hmC deposition on the gene body and at enhancers in cardiac cells. We thus provide the first genome-wide analysis of 5-hmC in the cardiomyocyte, and establish the role of this epigenetic modification in heart development and disease Overall design: Profiling of the transcriptome of embryonic, neonatal, adult, 1 week hypertrophic cardiomyocytes, sh-control and sh-TET2 cardiomyocytes. Two biological replicates were profiled for each cell type.

Project description:Methylation at 5-cytosine (5-mC) is a fundamental epigenetic DNA modification associated recently with cardiac disease. In contrast, the role of 5-hydroxymethylcytosine (5-hmC) – 5-mC’s oxidation product – is unknown in the context of the heart. Here, we assess the hydroxymethylome in embryonic, neonatal, adult and hypertrophic mouse cardiomyocytes, showing that dynamic modulation of hydroxymethylated DNA is associated with specific transcriptional networks during heart development and failure. DNA hydroxymethylation marks gene bodies of highly expressed genes and distal regulatory regions with enhanced activity. Pathological hypertrophy is characterized by a partial shift towards a fetal-like distribution pattern. We further demonstrate a regulatory function of TET2 and provide evidence that the expression of key cardiac genes, such as Myh7 is modulated by TET2-mediated 5-hmC deposition on the gene body and at enhancers in cardiac cells. We thus provide the first genome-wide analysis of 5-hmC in the cardiomyocyte, and establish the role of this epigenetic modification in heart development and disease Overall design: Profiling of 5hmC in E14.5, Neonatal, Adult, pressure-overload (TAC), sh-control and sh-TET2 isolated cardiomyocytes